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Steponenaite A, Lalic T, Atkinson L, Tanday N, Brown L, Mathie A, Cader ZM, Lall GS. TASK-3, two-pore potassium channels, contribute to circadian rhythms in the electrical properties of the suprachiasmatic nucleus and play a role in driving stable behavioural photic entrainment. Chronobiol Int 2024; 41:802-816. [PMID: 38757583 DOI: 10.1080/07420528.2024.2351515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 04/19/2024] [Indexed: 05/18/2024]
Abstract
Stable and entrainable physiological circadian rhythms are crucial for overall health and well-being. The suprachiasmatic nucleus (SCN), the primary circadian pacemaker in mammals, consists of diverse neuron types that collectively generate a circadian profile of electrical activity. However, the mechanisms underlying the regulation of endogenous neuronal excitability in the SCN remain unclear. Two-pore domain potassium channels (K2P), including TASK-3, are known to play a significant role in maintaining SCN diurnal homeostasis by inhibiting neuronal activity at night. In this study, we investigated the role of TASK-3 in SCN circadian neuronal regulation and behavioural photoentrainment using a TASK-3 global knockout mouse model. Our findings demonstrate the importance of TASK-3 in maintaining SCN hyperpolarization during the night and establishing SCN sensitivity to glutamate. Specifically, we observed that TASK-3 knockout mice lacked diurnal variation in resting membrane potential and exhibited altered glutamate sensitivity both in vivo and in vitro. Interestingly, despite these changes, the mice lacking TASK-3 were still able to maintain relatively normal circadian behaviour.
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Affiliation(s)
| | - Tatjana Lalic
- Translational Molecular Neuroscience Group, University of Oxford, Oxford, UK
| | | | - Neil Tanday
- Medway School of Pharmacy, University of Kent, Kent, UK
| | - Lorna Brown
- Medway School of Pharmacy, University of Kent, Kent, UK
| | | | - Zameel M Cader
- Translational Molecular Neuroscience Group, University of Oxford, Oxford, UK
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Lee DS, Kim TH, Park H, Kang TC. Deregulation of Astroglial TASK-1 K+ Channel Decreases the Responsiveness to Perampanel-Induced AMPA Receptor Inhibition in Chronic Epilepsy Rats. Int J Mol Sci 2023; 24:ijms24065491. [PMID: 36982567 PMCID: PMC10049714 DOI: 10.3390/ijms24065491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 03/06/2023] [Accepted: 03/10/2023] [Indexed: 03/17/2023] Open
Abstract
Tandem of P domains in a weak inwardly rectifying K+ channel (TWIK)-related acid sensitive K+-1 channel (TASK-1) is activated under extracellular alkaline conditions (pH 7.2–8.2), which are upregulated in astrocytes (particularly in the CA1 region) of the hippocampi of patients with temporal lobe epilepsy and chronic epilepsy rats. Perampanel (PER) is a non-competitive α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR) antagonist used for the treatment of focal seizures and primary generalized tonic–clonic seizures. Since AMPAR activation leads to extracellular alkaline shifts, it is likely that the responsiveness to PER in the epileptic hippocampus may be relevant to astroglial TASK-1 regulation, which has been unreported. In the present study, we found that PER ameliorated astroglial TASK-1 upregulation in responders (whose seizure activities were responsive to PER), but not non-responders (whose seizure activities were not responsive to PER), in chronic epilepsy rats. ML365 (a selective TASK-1 inhibitor) diminished astroglial TASK-1 expression and seizure duration in non-responders to PER. ML365 co-treatment with PER decreased spontaneous seizure activities in non-responders to PER. These findings suggest that deregulation of astroglial TASK-1 upregulation may participate in the responsiveness to PER, and that this may be a potential target to improve the efficacies of PER.
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Affiliation(s)
- Duk-Shin Lee
- Department of Anatomy and Neurobiology, College of Medicine, Hallym University, Chuncheon 24252, Republic of Korea
- Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon 24252, Republic of Korea
| | - Tae-Hyun Kim
- Department of Anatomy and Neurobiology, College of Medicine, Hallym University, Chuncheon 24252, Republic of Korea
- Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon 24252, Republic of Korea
| | - Hana Park
- Department of Anatomy and Neurobiology, College of Medicine, Hallym University, Chuncheon 24252, Republic of Korea
- Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon 24252, Republic of Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, College of Medicine, Hallym University, Chuncheon 24252, Republic of Korea
- Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon 24252, Republic of Korea
- Correspondence: ; Tel.: +82-33-248-2524; Fax: +82-33-248-2525
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Kim JE, Kang TC. Blockade of TASK-1 Channel Improves the Efficacy of Levetiracetam in Chronically Epileptic Rats. Biomedicines 2022; 10:biomedicines10040787. [PMID: 35453538 PMCID: PMC9030960 DOI: 10.3390/biomedicines10040787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/21/2022] [Accepted: 03/26/2022] [Indexed: 11/29/2022] Open
Abstract
Tandem of P domains in a weak inwardly rectifying K+ channel (TWIK)-related acid sensitive K+-1 channel (TASK-1) is an outwardly rectifying K+ channel that acts in response to extracellular pH. TASK-1 is upregulated in the astrocytes (particularly in the CA1 region) of the hippocampi of patients with temporal lobe epilepsy and chronically epilepsy rats. Since levetiracetam (LEV) is an effective inhibitor for carbonic anhydrase, which has a pivotal role in buffering of extracellular pH, it is likely that the anti-epileptic action of LEV may be relevant to TASK-1 inhibition, which remains to be elusive. In the present study, we found that LEV diminished the upregulated TASK-1 expression in the CA1 astrocytes of responders (whose seizure activities were responsive to LEV), but not non-responders (whose seizure activities were not controlled by LEV) in chronically epileptic rats. ML365 (a selective TASK-1 inhibitor) only reduced seizure duration in LEV non-responders, concomitant with astroglial TASK-1 downregulation. Furthermore, ML365 co-treatment with LEV decreased the duration, frequency and severity of spontaneous seizures in non-responders to LEV. To the best of our knowledge, our findings suggest, for the first time, that the up-regulation of TASK-1 expression in CA1 astrocytes may be involved in refractory seizures in response to LEV. This may be a potential target to improve responsiveness to LEV.
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Affiliation(s)
| | - Tae-Cheon Kang
- Correspondence: ; Tel.: +82-33-248-2524; Fax: +82-33-248-2525
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Li XL, Tang CY, Wang S, Zhao M, Wang XF, Li TF, Qi XL, Luan GM, Guan YG. Regulation of TWIK-related K + channel 1 in the anterior hippocampus of patients with temporal lobe epilepsy with comorbid depression. Epilepsy Behav 2021; 121:108045. [PMID: 34116339 DOI: 10.1016/j.yebeh.2021.108045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/11/2021] [Accepted: 04/30/2021] [Indexed: 02/08/2023]
Abstract
Epilepsy with comorbid depression has recently attracted increasing attention. Temporal lobe epilepsy (TLE) may represent an increased risk of developing depression, especially if the seizures do not generalize. The two-pore domain potassium channel-TWIK-related K+ channel (TREK-1) plays important roles in both epilepsy and depression. However, the changes in its expression in patients with epilepsy with comorbid depression remain unclear. In the present study, we analyzed depressive symptoms using neuropsychiatric scales in forty-two patients with drug-resistant TLE, who also underwent EEG in waking and sleeping states, as well as 3.0 T brain MRI. We tested for TREK-1 positive neurons and microglial cells in the anterior hippocampi of patients with drug-resistant TLE with and without comorbid depression (n=5/group). Approximately 31% of patients with TLE had comorbid depression (13/42). Meanwhile, the patients who had hippocampal sclerosis had much higher scores on the depression rating scale. The results indicated the contribution of hippocampal sclerosis to the development of depression. Immunostaining of TREK-1 channels was observed in neurons and glia in the anterior hippocampus. Increased immunoreactivity of TREK-1 neurons was observed in the hippocampi of patients with TLE with comorbid depression compared with nondepressed patients with TLE. TREK-1 was expressed in almost all microglia. Curiously, more activated TREK-1-positive microglia were observed in patients with TLE with depression than in those without depression. The results suggested that a change in TREK-1 immunoreactivity was involved, at least partly, in the development of depression as a comorbidity of TLE. Imbalance of the TREK-1 channel may be a potential target for the treatment of patients with epilepsy with comorbid depression.
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Affiliation(s)
- Xiao-Li Li
- Department of Neurology, Affiliated ZhongDa Hospital, Southeast University, Nanjing, China; Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Chong-Yang Tang
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Shu Wang
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Meng Zhao
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Xiong-Fei Wang
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Tian-Fu Li
- Department of Neurology, Sanbo Brain Hospital, Capital Medical University, Beijing, China; Beijing Key Laboratory of Epilepsy, Beijing, China; Center of Epilepsy, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Xue-Ling Qi
- Department of Pathology, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Guo-Ming Luan
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China; Beijing Key Laboratory of Epilepsy, Beijing, China; Center of Epilepsy, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China.
| | - Yu-Guang Guan
- Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China; Beijing Key Laboratory of Epilepsy, Beijing, China; Center of Epilepsy, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China.
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5
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Verhoog QP, Holtman L, Aronica E, van Vliet EA. Astrocytes as Guardians of Neuronal Excitability: Mechanisms Underlying Epileptogenesis. Front Neurol 2020; 11:591690. [PMID: 33324329 PMCID: PMC7726323 DOI: 10.3389/fneur.2020.591690] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/26/2020] [Indexed: 12/11/2022] Open
Abstract
Astrocytes are key homeostatic regulators in the central nervous system and play important roles in physiology. After brain damage caused by e.g., status epilepticus, traumatic brain injury, or stroke, astrocytes may adopt a reactive phenotype. This process of reactive astrogliosis is important to restore brain homeostasis. However, persistent reactive astrogliosis can be detrimental for the brain and contributes to the development of epilepsy. In this review, we will focus on physiological functions of astrocytes in the normal brain as well as pathophysiological functions in the epileptogenic brain, with a focus on acquired epilepsy. We will discuss the role of astrocyte-related processes in epileptogenesis, including reactive astrogliosis, disturbances in energy supply and metabolism, gliotransmission, and extracellular ion concentrations, as well as blood-brain barrier dysfunction and dysregulation of blood flow. Since dysfunction of astrocytes can contribute to epilepsy, we will also discuss their role as potential targets for new therapeutic strategies.
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Affiliation(s)
- Quirijn P. Verhoog
- Leiden Academic Center for Drug Research, Leiden University, Leiden, Netherlands
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Linda Holtman
- Leiden Academic Center for Drug Research, Leiden University, Leiden, Netherlands
| | - Eleonora Aronica
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, Netherlands
| | - Erwin A. van Vliet
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
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Eszlari N, Millinghoffer A, Petschner P, Gonda X, Baksa D, Pulay AJ, Réthelyi JM, Breen G, Deakin JFW, Antal P, Bagdy G, Juhasz G. Genome-wide association analysis reveals KCTD12 and miR-383-binding genes in the background of rumination. Transl Psychiatry 2019; 9:119. [PMID: 30886212 PMCID: PMC6423133 DOI: 10.1038/s41398-019-0454-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 01/31/2019] [Accepted: 02/13/2019] [Indexed: 12/12/2022] Open
Abstract
Ruminative response style is a passive and repetitive way of responding to stress, associated with several disorders. Although twin and candidate gene studies have proven the genetic underpinnings of rumination, no genome-wide association study (GWAS) has been conducted yet. We performed a GWAS on ruminative response style and its two subtypes, brooding and reflection, among 1758 European adults recruited in the general population of Budapest, Hungary, and Manchester, United Kingdom. We evaluated single-nucleotide polymorphism (SNP)-based, gene-based and gene set-based tests, together with inferences on genes regulated by our most significant SNPs. While no genome-wide significant hit emerged at the SNP level, the association of rumination survived correction for multiple testing with KCTD12 at the gene level, and with the set of genes binding miR-383 at the gene set level. SNP-level results were concordant between the Budapest and Manchester subsamples for all three rumination phenotypes. SNP-level results and their links to brain expression levels based on external databases supported the role of KCTD12, SRGAP3, and SETD5 in rumination, CDH12 in brooding, and DPYSL5, MAPRE3, KCNK3, ATXN7L3B, and TPH2 in reflection, among others. The relatively low sample size is a limitation of our study. Results of the first GWAS on rumination identified genes previously implicated in psychiatric disorders underscoring the transdiagnostic nature of rumination, and pointed to the possible role of the dorsolateral prefrontal cortex, hippocampus, and cerebellum in this cognitive process.
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Affiliation(s)
- Nora Eszlari
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary. .,NAP-2-SE New Antidepressant Target Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary.
| | - Andras Millinghoffer
- 0000 0001 0942 9821grid.11804.3cNAP-2-SE New Antidepressant Target Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary ,0000 0001 2180 0451grid.6759.dDepartment of Measurement and Information Systems, Budapest University of Technology and Economics, Budapest, Hungary
| | - Peter Petschner
- 0000 0001 0942 9821grid.11804.3cDepartment of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary ,0000 0001 0942 9821grid.11804.3cMTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
| | - Xenia Gonda
- 0000 0001 0942 9821grid.11804.3cNAP-2-SE New Antidepressant Target Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary ,0000 0001 0942 9821grid.11804.3cMTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary ,0000 0001 0942 9821grid.11804.3cDepartment of Psychiatry and Psychotherapy, Semmelweis University, Budapest, Hungary
| | - Daniel Baksa
- 0000 0001 0942 9821grid.11804.3cDepartment of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary ,0000 0001 0942 9821grid.11804.3cSE-NAP 2 Genetic Brain Imaging Migraine Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary
| | - Attila J. Pulay
- 0000 0001 0942 9821grid.11804.3cDepartment of Psychiatry and Psychotherapy, Semmelweis University, Budapest, Hungary
| | - János M. Réthelyi
- 0000 0001 0942 9821grid.11804.3cDepartment of Psychiatry and Psychotherapy, Semmelweis University, Budapest, Hungary ,0000 0001 0942 9821grid.11804.3cNAP2 Molecular Psychiatry Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary
| | - Gerome Breen
- 0000 0001 2322 6764grid.13097.3cSocial, Genetic and Developmental Psychiatry Centre, King’s College London, London, UK
| | - John Francis William Deakin
- 0000000121662407grid.5379.8Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK ,0000 0004 0417 0074grid.462482.eManchester Academic Health Sciences Centre, Manchester, UK ,0000 0004 0430 6955grid.450837.dGreater Manchester Mental Health NHS Foundation Trust, Prestwich, Manchester, M25 3BL UK
| | - Peter Antal
- 0000 0001 2180 0451grid.6759.dDepartment of Measurement and Information Systems, Budapest University of Technology and Economics, Budapest, Hungary
| | - Gyorgy Bagdy
- 0000 0001 0942 9821grid.11804.3cDepartment of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary ,0000 0001 0942 9821grid.11804.3cNAP-2-SE New Antidepressant Target Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary ,0000 0001 0942 9821grid.11804.3cMTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
| | - Gabriella Juhasz
- 0000 0001 0942 9821grid.11804.3cDepartment of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary ,0000 0001 0942 9821grid.11804.3cNAP-2-SE New Antidepressant Target Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary ,0000 0001 0942 9821grid.11804.3cMTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary ,0000 0001 0942 9821grid.11804.3cSE-NAP 2 Genetic Brain Imaging Migraine Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary ,0000000121662407grid.5379.8Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK ,0000 0004 0417 0074grid.462482.eManchester Academic Health Sciences Centre, Manchester, UK
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Ryoo K, Park JY. Two-pore Domain Potassium Channels in Astrocytes. Exp Neurobiol 2016; 25:222-232. [PMID: 27790056 PMCID: PMC5081468 DOI: 10.5607/en.2016.25.5.222] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/01/2016] [Accepted: 09/15/2016] [Indexed: 12/23/2022] Open
Abstract
Two-pore domain potassium (K2P) channels have a distinct structure and channel properties, and are involved in a background K+ current. The 15 members of the K2P channels are identified and classified into six subfamilies on the basis of their sequence similarities. The activity of the channels is dynamically regulated by various physical, chemical, and biological effectors. The channels are expressed in a wide variety of tissues in mammals in an isoform specific manner, and play various roles in many physiological and pathophysiological conditions. To function as channels, the K2P channels form dimers, and some isoforms form heterodimers that provide diversity in channel properties. In the brain, TWIK1, TREK1, TREK2, TRAAK, TASK1, and TASK3 are predominantly expressed in various regions, including the cerebral cortex, dentate gyrus, CA1-CA3, and granular layer of the cerebellum. TWIK1, TREK1, and TASK1 are highly expressed in astrocytes, where they play specific cellular roles. Astrocytes keep leak K+ conductance, called the passive conductance, which mainly involves TWIK1-TREK1 heterodimeric channel. TWIK1 and TREK1 also mediate glutamate release from astrocytes in an exocytosis-independent manner. The expression of TREK1 and TREK2 in astrocytes increases under ischemic conditions, that enhance neuroprotection from ischemia. Accumulated evidence has indicated that astrocytes, together with neurons, are involved in brain function, with the K2P channels playing critical role in these astrocytes.
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Affiliation(s)
- Kanghyun Ryoo
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul 02841, Korea
| | - Jae-Yong Park
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul 02841, Korea
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Abstract
This review attempts to give a concise and up-to-date overview on the role of potassium channels in epilepsies. Their role can be defined from a genetic perspective, focusing on variants and de novo mutations identified in genetic studies or animal models with targeted, specific mutations in genes coding for a member of the large potassium channel family. In these genetic studies, a demonstrated functional link to hyperexcitability often remains elusive. However, their role can also be defined from a functional perspective, based on dynamic, aggravating, or adaptive transcriptional and posttranslational alterations. In these cases, it often remains elusive whether the alteration is causal or merely incidental. With ∼80 potassium channel types, of which ∼10% are known to be associated with epilepsies (in humans) or a seizure phenotype (in animals), if genetically mutated, a comprehensive review is a challenging endeavor. This goal may seem all the more ambitious once the data on posttranslational alterations, found both in human tissue from epilepsy patients and in chronic or acute animal models, are included. We therefore summarize the literature, and expand only on key findings, particularly regarding functional alterations found in patient brain tissue and chronic animal models.
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Affiliation(s)
- Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock 18057, Germany
| | - Jakob Wolfart
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock 18057, Germany
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Ehling P, Bittner S, Meuth SG, Budde T. TASK, TREK & Co.: a mutable potassium channel family for diverse tasks in the brain. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/s13295-015-0007-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Bista P, Cerina M, Ehling P, Leist M, Pape HC, Meuth SG, Budde T. The role of two-pore-domain background K⁺ (K₂p) channels in the thalamus. Pflugers Arch 2014; 467:895-905. [PMID: 25346156 DOI: 10.1007/s00424-014-1632-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/09/2014] [Accepted: 10/12/2014] [Indexed: 12/15/2022]
Abstract
The thalamocortical system is characterized by two fundamentally different activity states, namely synchronized burst firing and tonic action potential generation, which mainly occur during the behavioral states of sleep and wakefulness, respectively. The switch between the two firing modes is crucially governed by the bidirectional modulation of members of the K2P channel family, namely tandem of P domains in a weakly inward rectifying K(+) (TWIK)-related acid-sensitive K(+) (TASK) and TWIK-related K(+) (TREK) channels, in thalamocortical relay (TC) neurons. Several physicochemical stimuli including neurotransmitters, protons, di- and multivalent cations as well as clinically used drugs have been shown to modulate K2P channels in these cells. With respect to modulation of these channels by G-protein-coupled receptors, PLCβ plays a unique role with both substrate breakdown and product synthesis exerting important functions. While the degradation of PIP2 leads to the closure of TREK channels, the production of DAG induces the inhibition of TASK channels. Therefore, TASK and TREK channels were found to be central elements in the control of thalamic activity modes. Since research has yet focused on identifying the muscarinic pathway underling the modulation of TASK and TREK channels in TC neurons, future studies should address other thalamic cell types and members of the K2P channel family.
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Affiliation(s)
- Pawan Bista
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, 48149, Münster, Germany
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Marinc C, Derst C, Prüss H, Veh RW. Immunocytochemical localization of TASK-3 protein (K2P9.1) in the rat brain. Cell Mol Neurobiol 2014; 34:61-70. [PMID: 24077856 DOI: 10.1007/s10571-013-9987-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Accepted: 09/13/2013] [Indexed: 01/06/2023]
Abstract
Among all K2P channels, TASK-3 shows the most widespread expression in rat brain, regulating neuronal excitability and transmitter release. Using a recently purified and characterized polyclonal monospecific antibody against TASK-3, the entire rat brain was immunocytochemically analyzed for expression of TASK-3 protein. Besides its well-known strong expression in motoneurons and monoaminergic and cholinergic neurons, TASK-3 expression was found in most neurons throughout the brain. However, it was not detected in certain neuronal populations, and neuropil staining was restricted to few areas. Also, it was absent in adult glial cells. In hypothalamic areas, TASK-3 was particularly strongly expressed in the supraoptic and suprachiasmatic nuclei, whereas other hypothalamic nuclei showed lower protein levels. Immunostaining of hippocampal CA1 and CA3 pyramidal neurons showed strongest expression, together with clear staining of CA3 mossy fibers and marked staining also in the dentate gyrus granule cells. In neocortical areas, most neurons expressed TASK-3 with a somatodendritic localization, most obvious in layer V pyramidal neurons. In the cerebellum, TASK-3 protein was found mainly in neurons and neuropil of the granular cell layer, whereas Purkinje cells were only faintly positive. Particularly weak expression was demonstrated in the forebrain. This report provides a comprehensive overview of TASK-3 protein expression in the rat brain.
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